Sanderling Plan - Western Hemisphere Shorebird Reserve Network

Climate change impacts: Climate change could have uneven impacts on the Sanderling
(since, as a long-distance migrant, it is subject to distant events) and on its prey supply (subject
to local events), which could potentially de-couple Sanderlings from their food supply at certain
key sites (e.g., timing of Horseshoe crab eggs at Delaware Bay, or drying of saline lakes in
interior regions). If this were to happen, Sanderlings may have limited flexibility for adaptation
to altered schedules or routes. Climate change could also influence other important factors during
migration, such as predation or susceptibility to disease.
BREEDING GROUNDS
There is ample evidence that high arctic areas are experiencing strong effects of climate
change, and these effects may potentially threaten the Sanderling. How is climate change
influencing habitat on the breeding grounds? Are Sanderlings resilient to these changes, or are
their distributions shifting and/or is breeding productivity changing? Will climate change result
in new species interactions, ones that might impact the Sanderling (e.g., through competition,
predation, disease)? And importantly, will there be a loss of the prey base as habitat structure
changes in response to altered (drying) weather patterns? Further research is needed to
understand Sanderling reproduction and survival in the changing High Arctic.
SOCIAL ECOLOGY (AND ITS IMPORTANCE TO CONSERVATION)
Sanderlings commonly occur in a range of group sizes – singles, tens, hundreds,
thousands, and even tens of thousands. Their occurrence in a wide range of flock sizes is unusual
for shorebirds, as most species tend to occur in more consistent (less variable) flock sizes.
Research is needed to understand the importance of social structure in Sanderling (and other
shorebird) populations. For instance, what is the structure and survival importance of social
systems? How stable and how flexible are social structures? Is the distribution of age and sex
classes during winter socially driven or maintained? Furthermore, does habitat loss disrupt social
structure beyond the obvious loss of food resources, translating into reduced fitness? If so,
conservation efforts that consider sites as interchangeable (i.e., food resources only), or that
consistently target sites that accommodate large aggregations of birds—but do not attempt to
protect the smaller sites—may not succeed in halting population declines.
WHSRN – Sanderling Conservation Plan, February 2010, v1.1 63